Local Structure of Human Hair Spatially Resolved by Sub-Micron X-Ray Beam

The study revealed a new region in the cortex of human hair near the cuticle boundary where intermediate filaments (IFs) are both aligned with the hair's axis and orientationally ordered in-plane, a contrast to the disordered IF arrangement deeper in the cortex. Additionally, the cuticle was found to contain β-keratin sheets instead of α-keratin, as indicated by the absence of a key diffraction feature. This research underscored the utility of sub-micron x-ray beams in examining the structures of complex, multi-phase systems.